When actuators or motors are being operated in motor vehicles, in particular when electrical steering systems or electronic servo-assisted steering devices or electrically adjustable steering columns are being operated, it is possible for disturbing noises to be produced by diverse components of the actuator system. Disturbing noises of this type may be produced by way of example by an electric servo drive or its electric motor, a toothed belt, a ball screw drive, etc. These noises may also be determined by the arrangements, in other words the frequency of the noise changes with the rotational speed of the electric motor and depends upon the design of the components (pole pair number, number of the windings of the rotor of the electric motor, teeth number of a motor pinion, etc.). The noises are in particular frequently characterized by individual, in particular conspicuous, frequencies or arrangements.
Above all, individual (tonal) noises are perceived by humans as being particularly disturbing even though such individual frequencies are in principle unavoidable in the actuator systems of motor vehicles, in particular in electrical steering systems. Conventional methods for reducing noise are frequently limited by having to observe other technical requirements and cost considerations.
Furthermore, the acoustic behavior of assemblies in a motor vehicle is subjected to a notable production series deviation. The acoustic behavior of the assemblies is therefore not known in the individual case and it is also not possible to ascertain any noise change occurring as the service life increases, since a corresponding sensor system is not available. In addition, improper use (misuse) may also produce mechanical changes in an assembly in such a manner that disturbing noises that frequently result in customer complaints or field complaints occur after the misuse event. This applies in particular when steering systems and electrically adjustable steering columns are used.